Re: "You make your money buying the boat, not selling it."
The guy is probably right. Still, most of us do not buy and sell boats every few years so it probably does not matter that much. And who buys a boat to make money???
In general, like a fair deal and will not try to haggle down a price just to save a few bucks. It's bad karma IMO. Treat others like you want to be treated.
Be kind, for everyone you meet is fighting a hard battle.